(1) Field of Invention
During recent years, the demand for flotation devices for confining floating water contaminants has grown tremendously. In the first place, a basic reason is the increasingly serious environmental risk due to more and more frequent oil discharges, whether or not intentional. The ever increasing incidence of such occurrences with resultant risk to the environment along our coasts has also resulted in stricter rules as to preparedness for these environmental problems when they do occur.
The requirements placed on water barrier flotation curtains are extensive, since many aspects regarding water pollution problems and their possible solution demand consideration. Thus, it is desirable that a curtain of the type in question be easy to handle, i.e., that it have a low weight and a small volume, that it can be presented in packages, such as rolls, which are easily handled, and that it can be easily led or reeled out and assembled into desirable lengths. Moreover, it is essential that the curtain can be towed in a simple manner, that it have favorable characteristics in sea environments, and that it can be simply removed from the water after use. However, the single aspect which is perhaps most essential of all is that the curtain, after use, should be capable of being destroyed readily, preferably on the spot, without having to resort to elaborate disposal arrangements or facilities. In this respect, no satisfactory solution to the problem has hitherto been suggested.
(2) Prior Art
Water barrier flotation curtains of many different types are known. Especially during the last few years, plastic curtains have been provided in many variations. However, numerous disadvantages are associated with such plastic curtains, in that the material can be destroyed by combustion only with difficulty. Thus, the plastic material fuses in a known manner when heated, and the air oxygen required for combustion cannot obtain access to the material to the extent required for combustion. Moreover, certain plastic materials, such as polyvinyl chloride, have the tendency of releasing poisonous gases during combustion which, of course, is an essential handicap.